Conan debuted in November 2010 following O’Brien’s acrimonious split with broadcaster NBC after his brief stint as host of the network’s flagship The Tonight Show.
The announcement comes amid reports that Jimmy Fallon will take over from Jay Leno as host of The Tonight Show.
O’Brien’s show gets about 900,000 viewers per episode – well below Leno, David Letterman and Jimmy Kimmel – but it has a younger median audience age than the other US late-night talk shows.
“We are proud to extend our relationship with Conan as he continues to forge the future of late night,” Michael Wright, TBS president and head of programming, said in a statement. “I just wish we didn’t decide to tell him on April Fools’ Day.”
Conan airs in Australia on GO!